Production Machining

MAY 2016

Production Machining - Your access to the precision machining industrial buyer.

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Mr. Mack says. Both milling spindles can perform tool changes completely independently of one another. Te use of HSK toolholders reduces the tool costs, as live toolholders are no longer necessary. Te option of operating the machine with a short bar loader with few personnel is only one of several automated handling solutions. For handling a large series of chuck parts, TFT has outftted the machines with integrated robot loading. A rigid system, the R300 is less susceptible to vibration. Tis characteristic has a positive efect on the precision of the fnished parts and on the tool life, allowing TFT to produce clean, smooth surfaces and eliminating secondary deburring of critical bores. Te two quill-guided motorized milling spindles are located in the center of the machine bed. Because of the axes arrangement, conventional cross-slides with tool carriers are no longer necessary. When combined with the play-free and wear- free hydrostatic circular guide, the system has a high stifness. Te B-axis swivel range of 270 degrees and the rapid traverse rate of 45 m/min support machining fexibility and high-speed opera- tion at TFT. Te identical turning spindles with the same synchronous design have a maximum power rating of 47 kW, a maximum speed of 3,500 rpm and a peak torque of 690 Nm. Learning by Doing TFT started this quest for efcient multitasking in the early 1990s, and lessons learned helped the company move forward. When the Blitzfre XX600 aluminum nozzle body was introduced by TFT, the company machined it in four operations in 2.5 hours per piece in two lathe operations and two mill operations. "Te frst two operations on the lathe were boring and secondary boring, plus milling detail, which is very time consuming," Mr. Mack says. "Te frst operation was expen- sive because we had to have our highest paid personnel setting it up and running it; the bore had to be indicated on each casting. Shimming the casting and tapping it around with a brass hand tool to get it located was how we got the initial correct runout set on the parts." Its second operation was easier to locate, and it allowed loading the part onto a precision ID workholder. Milling was next, which required two operations on a third and diferent machine because operators could not reach all the features on the horizontal lathe without doing the process in two operations. "All these operations created burrs, which required a secondary manual deburring operation so it could be assem- bled," Mr. Mack says. "All these operations and part handling amounted to 2.5 hours per part, not including deburring." Ten, the operators put the part on another multitasking machine: this one with one turret and one motorized mill head. At this point, they also started with Esprit CAD/CAM software. And although the part was done in one operation, the cycle time was still about 35 minutes. "It was a nice improvement for us, but the machine had some clearance issues, and the operators could not get all the deburring done on it," Mr. Mack says. "And it had some extreme tool overhangs." Ten, TFT management saw the R300 fve-axis turn-mill at an IMTS (International Manufacturing Technology Show) and made a purchase. Once implemented in the shop, the new R300 was utilized to machine the nozzle body. "We were not looking for a tremendous improvement in cycle time, but we did like the possibility of simultaneous machining with two motorized mill heads," Mr. Mack says. "We put some of our large-volume parts (5,000 parts per year) on the machines— couplings and nozzles that require a range of milling, turning, threading operations. With its large-tool capacity, the machines can work unattended." Te company's two R300s eliminate the need for four multitasking machines. Unexpected Benefts TFT management discovered the R300 provided a lot more opportunity for process improvement than expected—simul- taneous complete machining, reaching all the features of the part plus a deburring pass—all in one setup. Tis turn-mill machined the XX600 nozzle body in 15 minutes complete, including deburring. Te company saved not only cycle time, but man hours in deburring. A loading robot was also added to the mill-turn machine. "Parts are staged, and the robot self-loads. Tis allowed process improvement on this part," Mr. Mack says. "Once you have the machine programmed and take the human element out of the operation (deburring), you really save time." TFT thought it could shorten the cycle time, but it had not considered the rigidity of the machine and its positive efect on the part quality and the capability of the two milling heads for simultaneous machining. Plus, the tool magazine The Index R300 turn-mill machined the nozzle body in 15 min. complete, including deburring. MULTITASKING 36 PRODUCTION MACHINING :: MAY 2016

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